We all know how homemade pasta is made.
The dough that is made from durum or bread wheat flour, eggs and water is prepared for processing with the domestic machines formed of a pair of smooth rollers and a pair of cutting rollers.
The longest rolling phase comes after the mixing phase.
After taking pieces of dough and patting them by hand into flat, thick and even sheets, they are introduced between the pair of smooth rollers in the domestic machine, with the maximum opening between the rollers.
To get the right thickness, the opening between the two rollers is reduced with each successive pass of the dough.
The reduction between one pass and the next to reduce the thickness of the pastry, is limited by the adherence of the roller surfaces which must drag the pasta sheet to press it.
Current domestic pasta machines which have been on the market for years now, have steel rolling rollers with a nickel-plated surface.
Nickel plating has a dual purpose, it protects the steel rollers and gives a longer lasting attractive appearance.
The problem with a nickel-plated surface is that it is smooth and compact and offers little adherence.
This means that numerous different passes are needed between the original thickness of the pasta sheet to the final required thickness.
This poor adherence is worsened further when dry flour has to be sprinkled over the pasta if it is too damp.
This means that the shiny nickel-plated surfaces offer no adherence whatever, and the pasta has to be pushed by hand into the two rollers.
The idea had been considered to roughen the nickel-plated surface to make it more adherent, by satinizing for example, but, as food products are involved, this is not possible because too much nickel would be given off into the pastry, which, being a heavy metal, is considered as harmful.
The aim of the patent is to overcome these problems by improving surface adherence of the rollers without any release of metal particles.
This aim has been reached by using aluminum rollers with anodized surfaces, exploiting the microporous feature of the surface which increases adherence and hardens the surface of the aluminum, which by nature is soft, and creates very long-lasting surfaces.
In fact the feature of this patent is the excellent surface adherence given by the microporous surface layer, in the form of evenly distributed microscopic raisings and grooves.
The anodizing process improves the microporosity without reducing the hardness and resistance to wear.
In detail, the surface layer of the anodized rollers is formed of a porous layer of aluminum oxide being in crystalline alumina (Al2O3) form and being an amorphous metal which is extremely hard and wear resistant with a microporous surface that creates micro-roughness without releasing any metal particles.
The inventiveness in this patent lies in using the collateral feature of anodizing aluminum which ensures hardness and resistance to wear and creates the surface micro-roughness which improves adherence of the rolling rollers on the pasta machines.
The hardness and wear resistance properties in this specific patent are also very advantageous, because the aluminum used for anodizing the rollers is of moderate hardness and is not easy to dent and the wear resistance of the surface reduces to virtually zero the release of particles from the surface layer, and even in the event any particles were released, being alumina they are not considered harmful in food preparations.
As previously stated, the anodized alumina used improves adherence on the surface of the processing rollers (rollers and cutters) in aluminum or aluminum alloys, but as alumina is by nature abrasive, it presents a problem for the scraping blades.
The function of the scraper blades is to avoid any pasta remaining on the rollers, and when the metal blades come into contact with the surface of the rollers they create friction.
As we said above, the surface of the rollers is abrasive and tends to wear the edges where the blades come into contact.
As the blades must be flexible to function, either stainless steel or nickel-plated steel are preferably used because they are hard wearing.
As we know, with wear the material begins to detach and this metal material would enter the pasta that is being processed.
Therefore as the surface of the rollers is alumina (hard and abrasive), the answer to avoid the metal particles detaching from the scraper blades is to coat them with a resin film for food use, to clean the rollers removing any pasta deposits and able to gently resist the roughness of the roller surface for a long time.